Adding Prometheus charm

[osm/devops.git] / installers / charm / prometheus-k8s / reactive / prometheus.py

diff --git a/installers/charm/prometheus-k8s/reactive/prometheus.py b/installers/charm/prometheus-k8s/reactive/prometheus.py
new file mode 100644 (file)
index 0000000..9aa4f26
--- /dev/null
+++ b/installers/charm/prometheus-k8s/reactive/prometheus.py
@@ -0,0 +1,107 @@
+# Copyright 2021 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+#
+# For those usages not covered by the Apache License, Version 2.0 please
+# contact: legal@canonical.com
+#
+# To get in touch with the maintainers, please contact:
+# osm-charmers@lists.launchpad.net
+##
+
+from charms.reactive import when, when_not, hook
+from charms.reactive.flags import set_flag, clear_flag
+from charmhelpers.core.hookenv import (
+    log,
+    metadata,
+    config,
+    network_get,
+    relation_id,
+)
+from charms import layer
+from charmhelpers.core import hookenv
+import traceback
+
+
+@hook("upgrade-charm")
+@when("leadership.is_leader")
+def upgrade():
+    clear_flag("prometheus-k8s.configured")
+
+
+@when("config.changed")
+@when("leadership.is_leader")
+def restart():
+    clear_flag("prometheus-k8s.configured")
+
+
+@when_not("prometheus-k8s.configured")
+@when("leadership.is_leader")
+def configure():
+    layer.status.maintenance("Configuring prometheus container")
+    try:
+        spec = make_pod_spec()
+        log("set pod spec:\n{}".format(spec))
+        layer.caas_base.pod_spec_set(spec)
+        set_flag("prometheus-k8s.configured")
+        layer.status.active("ready")
+
+    except Exception as e:
+        layer.status.blocked("k8s spec failed to deploy: {}".format(e))
+        log(traceback.format_exc(), level=hookenv.ERROR)
+
+
+@when("prometheus-k8s.configured")
+def set_prometheus_active():
+    layer.status.active("ready")
+
+
+@when_not("leadership.is_leader")
+def non_leaders_active():
+    layer.status.active("ready")
+
+
+@when("prometheus-k8s.configured", "endpoint.prometheus.available")
+def send_config(prometheus):
+    layer.status.maintenance("Sending prometheus configuration")
+    cfg = config()
+    try:
+        info = network_get("prometheus", relation_id())
+        log("network info {0}".format(info))
+        host = info.get("ingress-addresses", [""])[0]
+
+        prometheus.configure(hostname=host, port=cfg.get("advertised-port"))
+        clear_flag("endpoint.prometheus.available")
+    except Exception as e:
+        log("Exception sending config: {}".format(e))
+
+
+def make_pod_spec():
+    """Make pod specification for Kubernetes
+
+    Returns:
+        pod_spec: Pod specification for Kubernetes
+    """
+    with open("reactive/spec_template.yaml") as spec_file:
+        pod_spec_template = spec_file.read()
+
+    md = metadata()
+    cfg = config()
+
+    data = {
+        "name": md.get("name"),
+        "docker_image": cfg.get("prometheus-image"),
+        "a_docker_image": cfg.get("alpine-image"),
+    }
+    data.update(cfg)
+    return pod_spec_template % data